OUR PLANET. 
187 
l^eptune has the most interesting history of all. 
It was first discovered by mathematicians. They 
carefully calculated the amount of disturbance due to 
the gravitation of an unknown body in the path of 
our planets as they neared a certain part of the heav¬ 
ens. They found that there must be a planet of 
definite mass in that particular position in the heav¬ 
ens. This was done by two mathematicians, an Eng¬ 
lishman and a Frenchman, working independently. 
The Englishman sent his figures to the royal astrono¬ 
mer, who put them into a jfigeonhole without ex¬ 
amination. About twenty years later the French 
astronomer sent his figures to the Berlin Observatory, 
requesting that examination of that part of the heav¬ 
ens be made with their telescope. The leading as¬ 
tronomer there took so little interest in the matter 
that he turned the papers over to some of his stu¬ 
dents, who directed the telescope to that part of the 
heavens described, and were rewarded by finding the 
disturber which has since been named Neptune. 
OUR PLANET. 
A few words about the earth must be added. It 
is, of course, the planet which concerns us most. 
The inhabitants of Yenus viewing our earth and 
Mars see nearly the same scenery on both. They see 
the poles of both covered with ice-caps, points of 
which extend, here and there, farther toward the 
equator. They see land-masses and bodies of water, 
clouds and storms. Mars is, in fact, a miniature earth 
one-fourth as large. 
